1. Field of the Invention
The present invention relates to a level, and more particularly, to a non-contact electronic level.
2. Description of the Prior Art
Various forms of levels have been used as devices to enable the operator to determine when a particular surface is horizontal. Early levels consisted of a body of liquid in an open vessel since liquid is known to form a flat, horizontal surface. The surface of the liquid formed a reference surface which served as the standard against which the horizontal character of a second surface was estimated (e.g., an inclination direction and an inclination angle). This basic principle has evolved into a bubble level where a bubble is trapped in a body of liquid, with the liquid being enclosed in an upwardly curved, clear tube. An improved design uses a transparent ball instead of the clear tube for holding the liquid, enabling the bubble to move in all four directions of the plane thereon so that the user does not need to pivot the level at an angle of ninety degrees over and over again while measuring.
FIG. 1 illustrates another conventional level 100 which has a casing 102, an electrolyte 104 which has an air bubble 108 floating thereon, and a plurality of metal electrodes 106. The electrolyte 104 is placed in the casing 102, and the metal electrodes 106 pass through the casing 102 and soak in the electrolyte 104. If the air bubble 108 moves along the surface of the casing 102 when the level 100 is tilted, the resistance between the metal electrodes 106 will change as the air bubble 108 moves. Therefore, the horizontal position of the level 100 can be detected using the change of such resistance.
However, the level 100 in FIG. 1 still suffers from numerous drawbacks:
1. After the metal electrodes 106 have been used for a period of time, the surface of the metal electrodes 106 will be corroded and the resistance thereof will be affected, such that the accuracy and sensitivity of the level 100 are reduced.
2. The electrolyte 104 must be changed regularly to maintain a proper ion concentration.
3. Even if the metal electrodes 106 and the electrolyte 104 are changed regularly, the resistance can still be varied by the gradual corrosion of the electrodes 106 and the gradual consumption of the electrolyte 104, thereby affecting the accuracy and sensitivity of the level 100.
4. The electrolyte 104 is vulnerable to the temperature of the environment, such that the temperature variation of the surrounding environment will affect the conductivity of the electrolyte 104, thereby reducing the accuracy and sensitivity of the level 100.